1. Field of the Invention
This invention relates to vehicle seats and to support assemblies for vehicle seats.
2. Description of the Prior Art
Prior vehicle seat support assemblies have included fluid springs that receive pressurized fluid so as to support the seat in a manner that isolates the seat occupant from vertical vehicle vibrations. The U.S. Pat. No. of Lowe, 3,661,176 discloses a time delay leveling valve whose operation supplies and exhausts fluid within a fluid spring to maintain the same vertical seat height regardless of the weight of the seat occupant. Time delay operation of the Lowe valve prevents the valve from transiently supplying and exhausting pressurized fluid within the fluid spring during abrupt vertical seat movement resulting from dynamic forces that act on the seat during vehicle operation. However, the vertical height at which the Lowe valve positions the seat is not adjustable, and relatively heavy seat occupants who are short waisted may find they are positioned at a lower vertical height than they desire. Likewise, relatively light, long waisted persons may find that they would be positioned at a higher position than they desire.
The U.S. Pat. No. of Radke et al 3,325,136 discloses a vehicle seat of the fluid spring type, and the level of pressurized fluid within the fluid spring thereof is adjustable to control the static or mean vertical seat position. The adjustment is provided by a valve which is controlled by a somewhat complex linkage that is either coupled or uncoupled with the valve by manual operation of the seat occupant. Coupling of the linkage to the valve permits the linkage to be adjusted to change the vertical height of the seat. However, the linkage must be uncoupled from the valve during normal vehicle operation to prevent the valve from transiently being actuated by the vertical seat movement resulting from dynamic vehicle forces.
Vehicle seats, whether of the fluid spring supported type or not, have heretofore included adjustable supports for the generally horizontal seat cushion on which the seat occupant sits as well as the generally vertical seat back against which the occupant leans. The U.S. Pat. No. of Hillman 2,646,839 discloses a vehicle seat whose cushion is longitudinally adjustable with respect to its seat back and also supported for vertical movement at both its forward and rearward ends to provide a desired tilted adjustment of the cushion. The U.S. Pat. No. of Harder, Jr. 3,784,174 discloses a seat having a seat cushion that is mounted for tilting movement with respect to its associated seat back but not for longitudinal adjusting movement. A bolt and compressible washer securement pivotally supports one end of the Harder seat cushion so as to permit vertical tilting movement of its other end.
Also, recliner mechanisms for controlling the vertical tilted position of vehicle seat backs and the backs of nonvehicle seats are shown by the following U.S. Pat. Nos.: Hogan 412,617; Hultgren 1,889,478; Norwood et al 2,809,691; Borisch Re. 24,528. Seat back recliner mechanisms function best if they are of a rugged and durable construction so as to provide a long lifetime of service.